1. Field of the Invention
The present invention relates to household appliances, and more particularly to cooling systems, such as those utilized in refrigerators, freezers, and air conditioners.
2. Background Art
In the usual operation of appliances, such as refrigerators, freezers, and air conditioners, the appliance includes a sensor inside which causes the initiation of the operation of a compressor based on preestablished consumer user settings (cooler or warmer) and a preset temperature associated with the setting established by the user. Normally the preset temperatures are the same for each user setting, independent of ambient temperatures in which the appliance is operated.
Accordingly, inaccuracies of temperature control or energy efficiency may occur when substantial variance occurs in the temperature of the ambient air. Normally, solutions to this problem have utilized an extra temperature sensor placed outside the appliance. In this arrangement, the outside temperature is detected by the extra temperature sensor is utilized to override or provide some additional control to the internal compressor or similar device.
A search of the background art directed to the subject matter of the present invention and conducted in the U.S. Patent and Trademark Office disclosed the following U.S. Letters Patent:
U.S. Pat. No. 5,293,755 pertains to a control system, including an outdoor temperature sensor for sensing outdoor temperatures outside of an enclosure to be temperature controlled and a second temperature sensor within the enclosure sensing the interior temperature. Differential circuitry provides appropriate adjustment or control.
U.S. Pat. No. 5,123,477 is a programmable temperature control for a thermal reactor. Here too, a first temperature sensor is included within the chamber. The second sensor is included to sense temperature of air supplied to the chamber. Computer monitoring of the sensors controls the temperature of the chamber as the result of information from both sensors,
U.S. Pat. No. 5,275,011 teaches a method of operating a refrigeration system in two operating modes. The first mode determining a preselected temperature range is user selected, while the second mode monitors ambient temperature and a dynamic set point temperature to control an internal combustion engine which is utilized to control the compressor of the refrigeration system.
U.S. Pat. No. 5,197,670 is similar to U.S. Pat. No. 5,275,011. It teaches a refrigeration system having a compressor driven by a prime mover. The mover being started and stopped in response to the difference between the temperature of the conditioned space and a selected set point. Again, two temperature sensors are employed, one of which is included within the air flow.
U.S. Pat. No. 5,070,932 is a thermostat which utilizes a fixed resistor in series with an ambient compensating thermistor for temperature control purposes.
Based on a thorough review of the above identified patents, we believe that none of the above teach, disclose or claim the novel combination of elements and functions found in the improved cooling system taught by the present invention.